This invention relates to a sheet separator in a recirculating document feeder for a copier/duplicator and, more specifically, to improved apparatus for guiding and driving the separator through its path of travel.
U.S. Pat. No. 4,076,408, issued Feb. 28, 1978, and U.S. Pat. No. 4,164,347, issued Aug. 14, 1979, disclose recirculating document feeders for a copier/duplicator wherein document sheets are fed seriatim along a path leading from the bottom of a stack of such sheets to a copying position and then back to the top of the stack of sheets. The recirculating feeders include a support for holding the stack of sheets and means for feeding the sheets along the path seriatim. A separator is engageable with the sheet that initially is on top of the stack for separating sheets in the stack that have been circulated along the path from those sheets in the stack that have not been circulated along the path. When the sheet that initially is on top of the stack reaches the bottom of the stack and is fed along the sheet path, the separator is returned to the top of the stack so that it again rests on the same sheet at the top of the stack of sheets. The sheet separator in such patents are driven in a rotary path about an axis.
During rotation of the separator back to the top of the stack it actuates a switch which provides a signal to a logic and control unit (LCU) to indicate that the entire set of document sheets has been circulated to the exposure position once. The LCU counts the number of copy sets that have been made and compares that count to the number of such sets requested by the machine operator.
While sheet separators and drives therefore of the type described in such patents have worked satisfactorily, the drive force applied to the separator also is applied to the document sheets. When only a few documents sheets are in the stack, the separator can cause damage to the sheets.
U.S. Pat. No. 4,231,562, issued Nov. 4, 1980, discloses a recirculating document feeder with a sheet separator that is driven through a generally rectilinear guide path by a solenoid that applies a linear force to the separator. One problem with such apparatus is that it requires a pair of springs to assure movement of a guide mechanism for the separator along the desired path. The springs increase the time and cost of assembling the separator. The apparatus of the present invention eliminates the need for the springs, and thus the cost of the springs and the time and cost of assembly of the springs. The present apparatus also requires less force from a solenoid than some prior designs, and is highly reliable.